In the present state of the art there is a great variety of pulp disintegrators, which include those of the vertical type, with the rotor located in the base of the vat (traditional rotor type), spiral and other types, cylindrical or polygonal tanks, and others of a high density inclined type or with a lateral feed.
In all these disintegration is brought about by the motion of the rotor which destroys the bales of waste paper or pulp and also sets up strong turbulence in this zone. Deflector plates slow the pulp down, returning the mass again towards the central rotor.
There are also different systems for the extraction of impurities on the market. The most common are those using endless bands or chains with buckets. These arrangements are restricted by the size of the pulper, the concentration of the pulp, the difficulty of handling it, their high energy consumption and their low efficiency.
This type of vertical pulper with a tank which is spiral in plan solves various problems which arise in pulp preparation.
When recycled paper is used as a raw material this generally contains a large quantity of solid impurities. These foreign bodies are concentrated in the vortex created by the rotor and often obstruct it in such a way that it losses all its disintegrating capacity. This gives rise to long down times in paper production because the rotor has to be cleaned and the system adjusted, which incurs a high time cost and unevenness in quality.
Likewise in pulpers in which the rotor is central, a central vortex forms above the rotor and the remainder of the material rotates in a mass around it, so a large part of the power consumed is converted into rotation of the whole mass and not into disintegration of the pulp.
With this innovative design of a spiral shaped pulper tank large impurities are driven along the hydraulic path defined by the spiral to the Archimedes screw, which extracts them, while negative pressure is produced in such a way that the mass does not gyrate around the rotor, compelling it to pass beneath the disintegrating rotor, with the appearance of hydraulic shear forces which favour a gentle cutting process, which is very useful with recovered fibres because in this way they are not shortened. Likewise, expulsion of pulp carried over by the impurities to the exterior is avoided by the continuous washing applied to the Archimedes screw and the material which it carries, and the recovery which takes place at the base of the screw on the pulper side.
Maintenance is simple because the rotor and the driving mechanism can be removed via the interior of the, tank. The impurity extraction area is easily cleaned and easy of access for repair.
The equipment consists of the following parts:
A cutting rotor with knives located in the base of the tank. PA1 A tank of spiral shape, open at the top and constructed of sheet metal with a flat base. PA1 An Archimedes screw for the extraction of impurities and foreign bodies. PA1 A motor and reduction gear to drive the Archimedes screw PA1 A motor and reduction gear to drive the cutting rotor. PA1 A panel for discharging and cleaning the Archimedes screw. PA1 Supporting columns for the equipment.